International Data Base
Population Estimates and Projections Methodology
June 2009
Overview
The U.S. Census Bureau has been preparing estimates and projections of the populations
of foreign countries since the 1960s. In the 1980s the Census Bureau released its first
comprehensive set of estimates and projections for over 200 countries and areas of the
world. Since then, the Census Bureau has routinely updated estimates and projections for
countries as new data have become available. Estimates and projections for countries, as
well as for regions and the world, are made available to the public, through the Census
Bureau’s International Data Base (IDB), located at Web site
http://www.census.gov/ipc/www/idb/.
The Census Bureau’s IDB estimates and projections have several distinguishing features.
For countries and areas recognized by the U.S. Department of State and which have
populations of 5,000 or more, population size and components of change are provided for
each calendar year beyond the initial or base year, through 2050.1 Within this time
series, sex ratios, population, and mortality measures are developed for single ages
through age 100-plus. As a result of single-year age and calendar-year accounting, IDB
data capture the timing and demographic impact of important events such as wars,
famine, and natural disasters, with a precision exceeding that of other online resourc
international demog
es for
raphic data.
The estimation and projection process involves data collection, data evaluation,
parameter2 estimation, making assumptions about future change, and final projection of
the population for each country. The Census Bureau begins the process by collecting
demographic data from censuses, surveys, vital registration, and administrative records
from a variety of sources. Available data are evaluated, with particular attention to
internal and temporal consistency.
The U.S. Census Bureau strives to base the